Multiblock copolymer, rubber composition, and tire

Abstract

A multiblock copolymer, obtainable by copolymerization of a conjugated diene compound and a non-conjugated olefin, is characterized in that: a structure of the multiblock copolymer includes A-(B-A) x and/or B-(A-B) x , wherein “A” represents a block portion constituted of monomer units of a non-conjugated olefin, “B” represents a block portion constituted of monomer units of a conjugated diene compound, and “x” represents an integer ≧1; content of the non-conjugated olefin portion is 50 mol %; 0 mol % <crystal content of the non-conjugated olefin portion 20 mol %; and 0% <degree of crystallinity of the non-conjugated olefin portion 40%. Vulcanized rubber having high fracture resistance and high crack resistance (thus a rubber composition and a tire each using the vulcanized rubber and having such excellent physical properties) can be manufactured from the multiblock polymer.

1 . A multiblock copolymer, obtainable by copolymerization of a conjugated diene compound and a non-conjugated olefin, wherein:
 a structure of the multiblock copolymer includes A-(B-A) x  and/or B-(A-B) x , wherein “A” represents a block portion constituted of monomer units of a non-conjugated olefin, “B” represents a block portion constituted of monomer units of a conjugated diene compound, and “x” represents an integer ≧1;   content of the non-conjugated olefin portion is ≦50 mol %;   0 mol % <crystal content of the non-conjugated olefin portion ≦20 mol %; and   0% <degree of crystallinity of the non-conjugated olefin portion ≦40%.   
     
     
         2 . The multiblock copolymer of  claim 1 , wherein the content of the non-conjugated olefin portion is in the range of 10 mol % to 40 mol %. 
     
     
         3 . The multiblock copolymer of  claim 1 , wherein the crystal content of the non-conjugated olefin portion is in the range of 5 mol % to 15 mol %. 
     
     
         4 . The multiblock copolymer of  claim 1 , wherein the degree of crystallinity of the non-conjugated olefin portion is in the range of 15% to 40%. 
     
     
         5 . A rubber composition, having as a rubber component the multiblock copolymer of  claim 1 . 
     
     
         6 . A tire, having the rubber composition of  claim 5 .